TOPIC: Shadow on Alpha Channel

Hi to all,
this time i try LW again (instead of Liquid) for an important project.
As you can see Liquid make a shadow right to the alpha channel, very simply.
LW make shadows only on the whole image, not on the alpha channel.
The logo is a TGA file.
How can i make the right shadow with LW without using other software?

This effect was created to enable the user to add a border and/or drop shadow to any image with an alpha channel. Border and shadow colours are independently adjustable, and two border generation modes are provided. Both can be anti-aliased or not as desired. Normally used to composite the result into a background image, it can also export all transparency, shadow and border data for use with other effects.